Paleobiology of firmground burrowers and cryptobionts at a Miocene omission surface, Alcoi, SE Spain

A well-preserved omission surface (sedimentary discontinuity) in an outcrop near Alcoi in southeastern Spain displays trace fossils and body fossils that reflect a dynamic benthic community during the Miocene (Langhian–Tortonian). This outcrop, besides being the type locality of Spongeliomorpha iberica Saporta, 1887, exhibits other abundant trace fossils, such as Glossifungites saxicava Łomnicki, 1886 and Gastrochaenolites ornatus Kelly and Bromley, 1984. These trace fossils are restricted to a single stratigraphic horizon and constitute a typical firmground ichnoassemblage of the Glossifungites ichnofacies. The interiors of some of the Glossifungites and Spongeliomorpha burrows were occupied by encrusting balanomorph barnacles (Actinobalanus dolosus Darwin, 1854). This paper is the first report of cryptic barnacles colonizing the interior of open burrows that constitute a typical firmground ichnocoenose in the fossil record. Detailed ichnologic study demonstrates that the ichnospecies Glossifungites saxicava stands as a valid ichnotaxon and is not a synonym of the ichnogenus Rhizocorallium, as has been suggested by some previous workers.